Need help with iscsi

[cbx]

Hello

I have 50 vps installed in 40 micro servers (microblade with atom C2750 and 8G of RAM), the microblade is connected to an QNAP ES1640DC-V2 (dual controller with 4 SSD cache and 12 SAS Near-line 6T) for storage VMs.

All servers have 2,5Gbs/ network interfaces and are connected to NAS with 6*10Gbs twinax cable.

The NAS have one pool in RAID10 with cache active.
For now, I connect only 2 ISCSI ressources with the 30T (max capacity of NAS as it in RAID10) with thin provisioning (one for 20 VMs and other for 30 VMs), in generally, this works, but have great problem when I delete an VM (disk about 100/200G), this produce an hight I/O delay in all VMs and return to the normal I/O when file is deleted.
Also have a bad result performance with an NFS freenas connected with an 10Gb/s with the vzdump (20/40Mbs)

It is the good strategy? Can you help me and give me some advise?

Thanks

 

[cbx]

Nobody to some advice about this??

 

[joblack]

You should analyze all possible error sources with specific performance tools (e.g. the tools in the sysstat package).

Maybe the network switches are not fast enough?
Are the Atom C2750 fast enough to utilize the 2.5gbit NIC?
Do you have network congestion? Check on your hosts for congestion? Do you have a performance bottleneck on your QNAP?

Generally you're description is not specific enough and I doubt that we could find the problem just based on a forum entry.

You should look at all your components (hosts, switch, cabeling, NAS/SAN) closely.

 

[manu]

For the FreeNAS backup part: you can only backup as fast as you can read
Make sure that you that FreeNAS is on a different network, and that you can read fast enought.

Whe you see the vzdump output like:
INFO: status: 92% (47804776448/51539607552), sparse 12% (6186778624), duration 319, 188/182 MB/s

here the backup job reads at 188MBs and write at 182MB/s on a moderately busy 1GB network during the last seconds.

If you only can read at 20MB/s it means that the san disks or the network is very busy.